Novel ditolyl alkanes and process for preparing the same



United States Patent Q NOVEL DITOLYL ALKANES AND PROCESS FOR PREPARING THE SAME John C. Petropoulos, Norwalk, Conn., assignor to American Cyanamid Company, New York, N. Y., a corporation of Maine N Drawing. Application November 21, 1956 Serial No. 623,557

6 Claims. (Cl. 260-668) This invention relates to a novel class of ditolyl alkanes having the general formula:

. R @Q C C it C a wherein R is an alkyl group having from 1 to 4 carbon atoms and R is an alkyl group having from 2 to 4 carbon atoms and to the products thus produced.

One of the objects of the present invention is to produce a novel class of ditolyl alkanes. A further object of the present invention is to produce a novel class of ditolyl alkanes which will have utility in a plurality of applications, particularly, for use in an oxidizing reaction whereby novel dicarboxylic acids are produced. These and other objects of the present invention will be discussed in greater detail hereinbelow.

This application is a continuation-in-part of my earlier application having the Serial No. 523,355, filed July 20, 1955, now U. S. Patent No. 2,848,486, entitled Novel Products and Process for" Preparing the Same. In my earlier application, I have disclosed and claimed methods for preparing certain alkylidene dibenzoic acids and their use in the manufacture of alkyd resins.

The novel hydrocarbons of the present invention may be used to producg when oxidized, some of theclass of the dicarboxylic acids disclosed and claimed in my application referred to hereinabove. The ditolyl alkanes of the present invention may be described as compounds in which the tolyl groups are joined together through a common, non-terminal carbon atom. The ditolyl alkanes in which the tolyl groups are joined together through a terminal carbon atom of the alkane are not readily oxidizable to the corresponding dicarboxylic acid and, in fact, there is often cleavage between the two tolyl groups in which oxidation takes place on the alkane group joining the tolyl groups rather than on the methyl groups on the aryl nuclei. Even though such a ditolyl alkane were to be oxidized successfully to the corresponding dicarboxylic 4 acid, the alkyd resin produced therefrom would show a lack of heat stability, light stability, lack of good color, colorstability, gloss and strength. Still further, such an alkyd resin would not be stable to mild oxidizing conditions such as air at elevated temperatures in the presence of metallic salt driers. The exact opposite is true of alkyd resins prepared from dicarboxylic acids resulting from ice 1 prepared by reacting a compound having the general formula:

.QEQ...

wherein R is an alkyl group having from 1 to 4 carbon atoms with a monoolefin having from 2 to 4 carbon atoms. Illustrative of these monoolefins are such materials as ethylene, propylene and butylene, either a, B, or isobutylene.

In the practice of the process of the present invention, it is desired to maintain, in the sphere of reaction, a temperature of between about 100 C. and 200 C. and preferably 130 C. to 160 C. v

Inasmuch as difiicultiesare sometimes experienced if the present process is-carried out at atmospheric pressure, it is far more desirable to carry out the alkylation reaction at a pressure between about 50 p. s. i. and 100G p. s. i. and preferably between-about 300 p. s. i. and 800 the oxidation of the ditolyl alkanes of the present invention.

The ditolyl alkanes of the present invention may be In alkylating the .1,1-ditolyl alkanes in the present invention, it is desirable to make use of a free alkali metal such as sodium, potassium, lithium, rubidium and cesium. Sodiumis actually'preferred. It is frequently desirable to make use of a promoter in minor. amounts which promoter cooperates withthe freealkali metal to accelerate the process and to increase the yield which promoter is in the nature of an organ'iccompound such as a hydrocarbon halide. The hydrocarbon nucleus may be alkyl, alkenyl, cycloalkyl, aralkyl, aryl and-alkaryl. The halogen atom may be either chlorine, bromine, iodine or fluorine. Chlorine and bromine are actually preferred. Other promoters may bev used such as alcohols, acids, ethers, nitrates, and cyano derivatives. Still further, one may use as a promoter a polycyclic hydrocarbon which is capable of reacting with a portion of said free alkali metal to form a metalized polycyclic hydrocarbon. Illustrative of the hydrocarbon halides which may be used in the practice of the process of the present .invention are ethyl chloride, ethyl bromide, 1i-propyl chloride, isopropyl chloride, n-butyl chloride, isobutyl chloride, secondary butyl chloride, tertiary butyl chloride, allyl-chloride, benzoyl chloride, tolyl chloride, tolyl bromide, cyclohexyl fluoride, 1,1-dichloro3,3-dimethyl butane and the like. I 1 p Among the alcohols which may be used in combination with the alkali metal; promoters forthe alkylation reation are ethanol, isobutanol, isoamyl alcohol and the like. One can additionally use carboxylic acids, particularly, aromatic mouocarboxylic acids such as benzoic acid, o-toluic acid and the like. Nitrobenzene and other nitroalcoholic hydrocarbons and nitroalkanes may also be used with alkali metals to form effective catalysts for the process. The cyano compounds include C H CN. In general, an excess of the alkali metal is employed relatively to the promoter which is also present in the catalyst mixture. Among the polycyclic hydrocarbons which are capable of reacting with a portion of said free alkali metal to form a metalized polycyclic hydrocarbon and used as a promoter of the alkylation reaction are anthracene, dihydro-anthracene, fiuorene, phenanthrene,

tetralin, diphenylmethane, o-diphenyl benzene and the i to promoter, respectively.

under conditions which do not assure thorough mixing. It is preferred to use more than about 2% by weight of free alkali metal based on the:ditolyl alkane reactant. The amount of promoter necessary depends on the mole ratio of free alkali metal to promoter. This mole ratio should be at least 2:1 up to about 10:1 free alkali metal Whenever desirable, even larger amounts can be used.

In order that the present inventionanay be more completely understood, the following examples are set forth in which all parts are parts by weight unless otherwise indicated. These examples are set forth primarily for the purpose of illustration and any specific enumeration of detail contained therein should not be interpreted as a limitation on the case except as is indicated in the ap,

pended claims.

Example 1 Into an autoclave there is introduced 105 parts of 1,1- di(p-tolyl)ethane, 5 parts of sodium and 1.5 parts of otoluic acid. The system is purged with nitrogen gas and then sealed. The autoclave is thenheated to about 170 C. and the pressure is released. There is then charged 11.8 parts of ethylene to 900 p. s. i. and the system is closed. The temperature is then maintained at 170 C. with intermittent addition of ethylene until no further pressure drop is experienced. This requires about 6 hours. The autoclave is then cooled and the reaction products are filtered and washed with hexane. The filtrates are combined, washed and distilled. The product produced is 2,2-di(p-tolyl)butane having a boiling point of 196 C. at 20 millimeters of pressure.

Example; '2

The preceding example is repeated in all essential details except that in the place ,of 1,1-di'(p-tolyl)ethane, there is substituted an equivalent amount of 1,1-di(ptolyl)propane and in the place of the o-toluic' acid, there is substituted an equivalent amount of o-chlorotoluene. The resultant product is a viscous liquid having a boiling point of 213-220" C. at 15 mm. of mercury. The prodnet is 3,3-di(pi-tolyl)pentane.

Among the ditolyl alkanes which may be prepared by a comparable process and which are representative of the ditolyl alkanes of the present invention are 2,2-di(ptolyl) butane; 2,2-di o-tolyl) butane; 2,2-di- (m-tolyl) butane; 2,2-di(p-tolyl)pentane; 2,2-di(o-tolyl)pentane, 2,2 di(m-tolyl)pentane; 3,3 di(p-tolyl)pentane; 3,3,- di(otolyl)pentane; 3,3- di(m-tolyl)pentane; 2,2-di(p-tolyl)- hexane; 3,3-di(o-tolyl)hexane; 3,3-di(p-tolyl)heptane; 3,3 di( o-tolyl) heptane', 4,4-di (p-tolyl heptane; 4,4-di (p-tolyl) octane; 5,5-di(p-tolyl)nonane; 5,5-di(o-tolyl)nonane; 5,5- di(m-tolyl) nonane, and the like.

R on? I t' on,

wherein R is an alkyl group having from 1 to 4 carbon atoms and R is an alkyl group having from 2 to 4 carbon atoms comprising reacting a compound having the formula:

I OH: H CH3 with a monolefin having two to four carbon atoms.

2. A process for preparing 2,2-di(p-tolyl)butane comprising reacting l,1-di(p-tolyl)ethane with ethylene.

3. A process for preparing 3,3-di(p-tolyl)pentane comprising reacting ,1,1-di( p-to'lyl)propane-with ethylene.

4. A compound having the general formula R 0% CH3 IL. CH; wherein R is an alkyl group having from 1 to '4 carbon atoms and R' is an alkyl group having from 2 to 4 carbon atoms.

5. 2,2-di (p-tolyl) butane. 6. 3,3-di(p-tolyl)pentane.

References Cited in the file of this patent UNITED STATES PATENTS 2,500,369 McCoubrey et al.. Mar. 14, 1950 2,682,561 Rogers et al. June 29, 1954 2,688,044 Pines etal. Aug. 31, 1954 2,719,871 Hiatt Oct. 4, 1955 2,721,885. Pines etal. Oct 25, 1955 2,769,850 Closson et alj.- Nov. 6, 1956 FOREIGN PATENTS" Great Britain Apr. 30, 1936 

1. A PROCESS FOR THE PREPARATION OF A HYDROCARBON HAVING THE FORMULA:
 4. A COMPOUND HAVING THE GENERAL FORMULA 